题干

寒冷的冬天,利用温室进行蔬菜种植,可以提高经济效益,但需要调节好温室的光照、湿度、温度和气体,以提高产品的质量,下列措施及方法正确的是(   )
①建造温室大棚时使用蓝紫色的塑料薄膜,以提高光合强度 ②适当增加光照,以补充冬季阳光的不足 ③向温室内定期施放适量二氧化碳气体,以增加光合强度 ④向温室内定期释放氧气,以降低呼吸作用强度 ⑤温室内保持适宜的昼夜温差,有利于有机物的积累


A:②④⑤

B:①②④

C:②③⑤

D:③④⑤

上一题 下一题 0.0难度 选择题 更新时间:2019-04-23 10:43:48

答案(点此获取答案解析)

B

同类题5

   Scientists are placing robotic dogs in the homes of lonely old people to test whether they can improve the quality of life for humans. Alan Beck, an expert(专家) in human-animal relationship, and Nancy Edwards, a professor of nursing, are leading the animal-assisted study on the effect of robotic dogs on old people’s depression (沮丧) , physical activity, and life satisfaction.
   In the study, the robot, called AIBO, is placed for six weeks in the houses of some old people who live alone. Before placing AIBO in the home, scientists will collect baseline data(数据) for six weeks. These old people will keep a diary to note their feelings and activity before and after AIBO. Then, the scientists will review the data to test if it has produced any changes in the life of its owner.“I talk to him all the time, and he responds to my voice,” says a seventy-year-old lady. “When I’m watching TV, he’ll stay in my arms until he wants down. He has his own mind.”
   The AIBOs respond to certain orders. The scientists say they have some advantages over live dogs, especially for old people. Often the elderly are disabled and cannot care for an animal by walking it or playing with it. A robotic dog removes exercise and feeding concerns.
“At the beginning, it was believed that no one would relate(与……相关) to the robotic dog, because it was metal and not furry.” Beck says. “Hopefully, down the road, these robotic pets could become a more-valuable health helper. They will record their masters' blood pressure, oxygen levels or heart rhythms(心律). AIBOs may even one day have games that can help stimulate(刺激) older people's minds.”